1. Field of the Invention
The present invention relates to a high voltage transformer for a backlight power source, and more particularly to a high voltage transformer for a backlight power source in which windings may be wound upward layer by layer on a bottom of a windings trough, which is facilitated by a novel structural design of a windings base when the windings are wound across an isolating wall so that a voltage bearing ability and stability of the high voltage transformer is enhanced.
2. Description of the Related Art
FIGS. 1A, 1B and 1C are respectively a side view, partial view and partial side view of a conventional transformer. As shown, the transformer 1 is composed of a windings base 11, a core 12 and windings 13. Exterior to the windings base 11, a plurality of isolating walls 111 are disposed, through which a primary side region 14 and a secondary side region 15 are formed. Through the isolating walls 111, the secondary side region 15 is further divided into a multitude of windings troughs 16 in which the windings 13 are disposed in turn.
Within a hollow structure of the windings base 11, the core 12 is received. As such, formation of the transformer 1 is completed. Since the transformer 1 has to meet the requirement of voltage bearing, the plurality of troughs are provided to isolate the voltage. However, since the isolating walls 111 are too high and thin (typically 0.4 mm in thickness), distance between two such adjacent troughs 16 is insufficient, leading to an insufficient voltage bearing ability of the troughs 16. On the other hand, when the coil of the windings 13 is intended to be laid out through a cutout opening 112 onto another windings trough 16, the coil strides from the top to the bottom through the isolating wall 111. This causes windings 13 wound on the next trough 16 in contact with the stridden coil and causes windings 13 of different voltages flown therein to interfere to each other and thus the voltage bearing ability is reduced. In this case, characteristics of the transformer 1 are unstable and exception would generally occur. In response to this problem, more windings troughs are generally suggested. However, issues of cost, dimension and layout space may be additionally involved in this design.
U.S. Pat. No. 6,937,129 of Hsuch et al. discloses a transformer with different coil winding densities. The flanges 313 shown in FIG. 3a include the cutout openings for the coils 312a and 312b to pass through. However, Hsuch does not teach or suggest to prevent the stridden coil from contacting the wound windings.
U.S. Pat. No. 6,936,379 of Kondo discloses a coil device which is provided with a plurality of winding drums on a bobbin with a partition formed between flanges at both ends of the bobbin. Although the slit 7 has a corner 7a shown in FIG. 1 or an one-side radiused portion 7b shown in FIG. 5, Kondo still does not teach or suggest to prevent the stridden wire “w” from contacting the wound windings.
From the above discussion, it can be readily known that such conventional transformer is inherent with some drawbacks and needs to be addressed and improved.
In view of these problems encountered in the prior art, the Inventors have paid many efforts in the related research and finally developed successfully a high voltage transformer for a backlight power source, which is taken as the present invention.